To understand the underlying mechanisms of regulating prostatic growth, we have focused our attention on the stromal-epithelial interaction. The following goals have been accomplished: 1) Rat prostatic tissues have been dissociated into single cell suspensions. Pure epithelial cells were isolated and characterized. Morphological and biochemical characterizations of stromal cells are presently under investigation. 2) Several biochemical methodologies were developed to assess the responsiveness of epithelial cells to stromal induction. These include steroid metabolism, androgen receptor assay, 2-dimensional polyacrylamide gel electrophoresis and enzyme activity assay. These methodologies have been applied to analyze the stromal-epithelial interaction in the developing prostate. 3) Human BPH tissues were successfully grown in nude mice. The influence of embryonic mesenchyme on human BPH growth and development is under investigation. 4) To evaluate the inductive potential of adult prostate to embryonic epithelium isolated from either urogenital sinus or bladder, a recombinant experiment was developed. Results indicate that adult prostate (stroma?) positively programmed the development of embryonic epithelium to prostate gland.